Research On The Up/Downconversion Luminescence Properties Of Yb³⁺/Er³⁺,Yb³⁺/Tm³⁺,Eu³⁺ Doped Composite Oxides

In recent years,with the development of science and technology,rare earth up/downconversion materials have been widely used in the fields of physical optics,surface chemistry,biomedicine and magnetism due to their good chemical and physical properties,such as low toxicity,long luminescence lifetime,sharp emission band and so on.However,the up/downconversion luminescence efficiency is not high enough in practical application.In this paper,we improved the upconversion luminescence properties of Yb³⁺/Er³⁺and Yb³⁺/Tm³⁺doped composite oxides and the downconversion luminescence properties of Eu³⁺ion doped composite oxides,as follows:A series of Sc₂O₃:5 mol%Yb³⁺,2 mol%Tm³⁺,x mol%Ca²⁺（x=0,10,20,30,40,50,60,70,80,90）and Sc₂O₃:5 mol%Yb³⁺,1 mol%Er³⁺,x mol%Ca²⁺（x=0,10,20,30,40,50,60,70,80,90）samples were successfully prepared through a high-temperature solid-state method.In our paper,the evolution of crystal phase from cubic phase Sc₂O₃ to orthorhombic phase CaSc₂O₄ and then to cubic phase Ca O was investigated with the increase of Ca²⁺ion doping concentration.When Ca²⁺ion doping concentration is about 40 mol%,CaSc₂O₄ co-doped with Yb³⁺/Er³⁺has the maximum red emission intensity（666 nm）which is increased by 39.5 times than that of Sc₂O₃ microcrystals.Similarly,the maximum near-infrared emission intensity（807 nm）in CaSc₂O₄ co-doped with Yb³⁺/Tm³⁺is enhanced by 9times than that of Sc₂O₃ microcrystals when Ca²⁺ion doping concentration is about 40 mol%.A series of Eu³⁺-doped ReMO₃（Re=Lu/Y/La;M=B/Al）phosphors have been synthesized via a high-temperature solid-state method.In this paper,the change of Eu-O charge transfer band in the Eu³⁺doped ReMO₃ phosphor was investigated.We found that the Eu-O charge transfer band was red-shifted and the full width at half maximum increased with the increase of the cation radius from Lu³⁺ion to Y³⁺ion and to La³⁺ion in Eu³⁺-doped ReMO₃ matrices.With the change of cation in the matrices from B³⁺ion（0.27?）to Al³⁺ion（0.535?）,the red-shift of the Eu-O charge transfer band occurred,and their the full width at half maximum increased.